Spermacoce capitata Ruiz & Pav.

Global description

Spermacoce capitata is a generally erect plant with a simple or little branched axis. The stem is square, glabrous to sparsely pubescent. The leaves are simple, sessile opposite and decussate, with generally at their base smaller leaves giving an aspect of whorl. They are narrowly lanceolate, with acute wedge-shaped apex and base. The margin is entire, both sides glabrous to very finely pubescent. At the base of the leaves is a stipular collar with 4 to 9 filiform teeth. The inflorescence consists of a large hemispherical terminal glomerulus and small axillary glomeruli. The glomerulus is subtended by 2 to 5 involucral foliaceous bracts. The calyx is tubular at the base and ends in 4-5 narrow lobes. The corolla is large, white, and consists of a tube topped by 4 outwardly curled petals. The fruit is a capsule.

General habit

Spermacoce capitata is an upright, mostly sufrutescent species. The axis is usually simple but can be more or less branched. It grows to 30-120 cm in height.

Undergroud system

The root is taproot.

Stem

The stem is clearly quadrangular, 1 to 3 mm in diameter. It may be glabrous or sparsely pubescent between the angles, to densely pubescent between the angles.

Leaf

The leaves are simple, opposite and decussate and sessile to subsessile. Each pair of leaves usually has smaller leaves at its base, giving a whorled appearance. At the base of the leaves is a stipular collar 3 to 4 mm high and 2 to 4 mm wide. It is puberulent to densely hirsute. It is surmounted by 4 to 9 filiform teeth 2 to 10 mm long. The leaf blade is membranous to subcoriaceous, narrow lanceolate, linear or elliptic, 1 to 9.5 cm long and 1.5 to 16 mm wide. The apex and base are acute wedge-shaped. The margin is entire, sometimes slightly revolute. Both sides are glabrous to pubescent. The lateral veins are pinnate, inconspicuous and slightly impressed on the upper face and conspicuous and prominent on the lower face.

Inflorescence

The inflorescence consists of a large terminal hemispherical glomerulus 7-15 mm high and 11-20 mm in diameter and small axillary glomeruli. The glomeruli are subtended by 2 to 5 involucral, foliose, linear lanceolate bracts, 2 to 5 cm long and 1.5 to 3.5 mm wide.

Flower

The flowers are subtended by a 2-4 mm long subulate bract. The calyx and hypatium form a tube 3.5-5 mm long, glabrous in the lower half and puberulent in the upper half. It is surmounted by 4 to 5 linear to subulate lobes, 1 to 2.5 mm long, equal to subequal, densely hispid at the margins. The corolla is large, clearly longer than the calyx, white in colour, 3.8 to 6.5 mm long. The base forms a slightly flared tube at the top, 2-4 mm long and 1-2.5 mm in diameter at the orifice. It is hairless. It is surmounted by 4 lanceolate to triangular lobes, 1.2 to 3 mm long, sparsely pubescent and often scurved. The 4 stamens between the corolla lobes protrude beyond the aperture and are as long as the corolla lobes, with bluish grey anthers. The style is 4-7 mm long, filiform, white, slightly longer than the stamens, the stigma slightly thickened at the apex and scarcely bilobed.

Fruit

The fruit is a capsule with two longitudinal chambers, forming an inverted cone 2 to 3 mm long and 0.8 mm wide. It is sparsely to densely pubescent at the top and glabrous at the bottom.

Seed

The seed is oblong linear, convex dorsally with a median canal ventrally, 1.2 mm long and 0.5 mm in diameter. It is orange-brown in colour, shiny. The dorsal convex side is punctuated with 16 to 18 cells.

Origin

Spermacoce capitata is native to and only occurs in Central America and the tropical part of South America.

https://www.gbif.org/species/2892008